Adjustable mounting means for a convergence assembly



March 110, 1970 A. M; ANTHONY 3,500,274]? ADJUSTABLE MOUNTING MEANS FORM CONVERGENCE ASSEMBLY Filed April 5, 1968' 2 Sheets-Sheet 1 A nag,

I Inventor- :Hbe'rl: M MKAIA March 10, 1970 A, M, NQTHONY v 3,500,270

' ADJUSTABLE MOUNTING MEANS FOR A CONVERGENCE ASSEMBLY Filed April 5, 1968 2 Sheets-Sheet z I'nve n'tor Albert M. fl-nthom QMK-QWe I fl-k'bomea-s United States Patent 3,500,270 ADJUSTABLE MOUNTING MEANS FOR A CONVERGENCE ASSEMBLY Albert M. Anthony, Conneaut, Ohio, assignor to Walter Kidde Company, Incorporated, Geneva, Ohio, a corporation of New York Filed Apr. 3, 1968, Ser. No. 718,403 Int. Cl. H013 29/70 US. Cl. 335212 11 Claims ABSTRACT OF THE DISCLOSURE A convergence assembly having adjustable features to permit secure mounting on necks of varying diameters of cathode ray tubes. A three-part housing is used to hold the three coils normally used with a tri-gun tube. Each part is separated 120 from its adjoining parts, and the parts are separable to a limited degree to vary the diameter of a central bore defined by the inner ends of the parts. Arcuate sections project from the perimeter of the bore and are engageable with an annular member which securely clamps the convergence assembly around the neck of a given diameter of a tube. The arcuate sections and the annular member are provided with means to enhance the clamping operation.

This invention relates to a convergence assembly for a color television cathode ray tube, and particularly relates to an assembly which ha adjustable mounting features and improved clamping means to positively mount such an assembly on necks of varying diameters of cathode ray tubes.

Color cathode ray tubes have three electron guns in spaced relation to the axis of the tube, and the beam of each gun is directed to illuminate phosphor dots of a certain color on the screen of the tube. The phosphor dots are usually arranged in arrays for each color, and the electron beam from each gun passes through an aperture screen or shadow mask which has a single set of holes in the same geometric configuration as each array of dots. When the electron beam travels its intended course, it illuminates only those dots which produce the intended color represented by the gun which originated that electron beam. The electron beams from the guns are aimed to converge upon the mask, and thereafter the beams diverge as they pass through the holes and arrive at the screen as three individual beams.

The beams may be aimed to converge on the center of the mask, but problems arise when the beams sweep from side to side and up and down. The convergent point of the beams sweeps in an arc which moves it away from the mask at points other than the center of the mask. Convergence coil assemblies have been devised and-are used to meet this problem. The coil assemblies are spaced 120 around the neck to coincide with the pole pieces of the electron guns. The beams must converge on the mask so that each beam passes through a hole in the mask at a correct angle to strike the corresponding phosphor dot on the screen. Dynamic convergence corrects for variations in length from the deflection point to the aperture mask as the beam travels from the center to the edge of the mask. Each of the coils is generally in the shape of a horseshoe, or may be a unit having two ferrite pieces. Each piece has a coil wrapped around it, and the vertical and horizontal convergence currents pass through the coils to control the convergence at the mask during the sweep of the beams.

Patented Mar. 10, 1970 Dynamic convergence assemblies of the foregoing type should be accurately and positively mounted on the neck of the tube so that each coil is properly aligned with the pole pieces within the tube. Coil pieces have been directly mounted to the neck to provide essentially a custom mounting, but this is understandably costly and not desirable. Assemblies may also be available with housings or supporting brackets for the coils and means to clamp said units directly to the neck of the tube. Such assemblies must, of course, be designed for a neck of a particular diameter, and such assemblies generally call for diflicult clamping operations because of limited working space.

It is one important object of the present invention to provide a convergence assembly which can be efficiently and securely mounted to necks of varying diameters on color cathode ray television tubes.

Another important object is a convergence assembly which can be positively mounted to the neck of a television tube to assure the desired and correct spacing between the three coils of the assembly.

It is still another important object to provide the convergence assembly which can be mounted in an improved manner on necks of color television tubes, but which assembly can be manufactured at economical cost.

Yet another important object is a convergence assembly which can be positively and effectively clamped to the neck of a color television tube by actuating means spaced from the neck to thereby allow easily accessible clamping operation.

A still further important object is a convergence assembly where a desired adjustability of the assembly is attained by angularly displaceable parts, and wherein such parts are displaced to a given degree within their separable range. Such parts are positively clamped by means which effectively prevent rotation of the assembly on the neck, and which effectively and positively position the parts at spacings of 120 on the neck of the color tube.

Objects such as the foregoing are attained, together with still other objects which will occur to practitioners, upon considering the invention of the following disclosure, including drawings wherein:

FIGURE 1 is a perspective view showing the convergence assembly mounted on the neck of a color television cathode ray tube;

FIGURE 2 is a side elevational view, on an enlarged scale, of the convergence assembly mounted on the neck of the tube;

FIGURE 3 is a back elevational view along line 33 of FIGURE 2;

FIGURE 3a is an enlarged fragmentary isometric view showing the means for limiting angular displacement of the parts of the assembly;

FIGURE 4 is a front elevational view taken along line 4-4 of FIGURE 2;

FIGURE 5 is an isometric view of a clamping member used in the assembly; and

FIGURE 6 is a fragmentary isometric view showing locking means on the assembly parts which cooperatively engage with the clamping member of FIGURE 5.

The use of the same numerals in the various views will indicate a reference of the same structures, parts or elements, as the case may be.

A cathode ray color television tube is shown in FIG- URE l, and such a tube includes a tube base 10, a neck 12, a flaring bell 14 and a front screen (not shown) in which the arrays of phosphor dots are distributed. The

neck of the tube is shown with a conventional deflection yoke 16, together with a housing part 18 which may be used for clamping and repositioning the deflection yoke. The convergence assembly is shown generally as 20 mounted on the neck in positively clamped position so that its three coil members are accurately aligned with pole pieces within the neck of the tube (not shown).

The convergence assembly includes a housing having three angularly placed parts 22, 24, and 26. The longitudinal axis of each part, which passes through the center of a central opening 28, is spaced 120 from the axis of the immediately adjoining parts. The inner ends of the parts are arcuately formed as in 22a, 24a and 26a. The arcuate ends, in combination, participate in the definition of the substantially circular and centrally positioned opening 28. The diameter of such a bore is generally dimensioned so that it may be adjusted for mounting on most necks of color television tubes. The bore may be varied in diameter to match different size necks by angularly displacing the parts 22, 24 and 26 away from one another. This is accomplished by providing limiting separable means which will be described later in greater detail.

The structural details of one of the parts 22, 24 or 26 shall now be described, and it should be understood that such a description will apply to the other parts. Each part has a supporting frame having a substantially planar outer end 30 and planar sides 32 and 34. The arcuate inner end is flanked by two displacement limiting means 35A and 35B which are angularly disposed. One such means 35A includes a projecting locking lug 36 which has an end portion 38 with flanges 38a and 38b projecting outwardly from the sides of a body member 40. The locking lug 36 projects tangent to the opening 28 and at an angle relative to side wall 32 so that the longitudinal axis of the projecting locking lug is about 60 to an adjoining side wall such as 34.

The other displacement limiting means 3513 has a locking chamber 44, which has an entry 46 of smaller dimension than the side-to-side dimension of the chamber. The width of the entry 46 permits the body 40 of the locking lug to be translated therethrough, but does not permit the flanges 38 to move out of the chamber 44. A shoulder 37 is at the end of the body member 40 opposite the flanged end portion 38. A U-shaped edge 39 on locking chamber 44 defines the reduced entry width 46, and also operates as an abutting surface with shoulder 37 to limit the displacement of the parts in reducing the diameter of the central opening 28. The flanged end portion 38 on the locking lug 36 abuts the edge 39 when the parts are angularly displaced in a direction to increase the diameter of the opening 28. It will be seen that a locking lug on each part is aligned for interlocking engagement with a locking chamber on an adjoining part and vice versa.

A coil assembly 48 is positioned in each part. Integrally formed angle ribs 50 and 52 abut the sides of the coil assembly, and a straight rib 53 abuts the top of the coil assembly. Sockets 54 and 56 are located towards the inner end of the part, and position the ends of ferrite pieces which protrude from the coil assembly. Thin blades 60 and 62 of ferromagnetic material are inserted in slots 60a and slightly recessed from arcuate surface 22a, 24a or 26a adjacent to the bottom of sockets 54 and 56 to extend the magnetic path from ferrite pieces 55 to the surface of the neck of the tube.

Each part is provided with four integrally formed pins 68 extending from the frame parallel to the axis of the opening 28 and generally located at the four corners of the frame 29. Such pins are adapted to frictionally engage a corresponding aperture 70, in a cap 72. The inner end of the cap has an arcuate wall 74 which is disposed on a radius of the same length as the radius upon which the arcuate inner ends 22a, 24a, and 26a of the frame 29 are disposed. When the cap 72 is mounted on the frame 29, a continuous arcuate segment is obtained which, together with the other ec p ernent y cuate segments of the other parts, defines the central opening 28 of the assembly. The cap 72 has an angular stub portion 76 which completes the chamber 44 of the angular limiting means 353. The cap 72 has a raised central portion 78, and this raised portion 78 defines a recess which accommodates any projecting portions of the coil assembly 48.

The convergence assembly is positively clamped on the neck of the television tube by clamping means on the front of the convergence assembly as best seen in FIG- URES 4 through 6. The front end of the assembly shows the other sides of the parts 22, 24 and 26, and each part is shown as having a cross-strip 80 with an irregular edge 80a formed by a plurality of quadrilateral cut-outs of different sizes and positions. Straight portion 80b of thestrip 80 is adapted to be positioned against portions of the coil assembly 48 which project outwardly from the housing part.

The parts 22, 24, and 26 have integral arcuate wall sections 82, 84 and 86 which project from the perimeter of the rear side of the opening 28, and such sections are normal to the plane of the opening. The arcuate sections 82, 84 and 86 have inner surfaces which are extensions of inner arcuate surfaces 22a, 24a and 26a of the housing parts, respectively. Each housing part has a continuous surface formed by the surface 74, one of the surfaces 24a, 24b or 240, and the surfaces of one of the sections 82, 84, and 86, and the continuous surfaces of the three housing parts together form a clamping surface in abutment with the neck of the television tube.

The convex side of the arcuate wall sections 82, 84 and 86 have serrated areas at opposite ends 82a and 82b. The serrations are formed by grooves 82c extending inwardly from the concave surface of the wall sections 82, 84 and 86, the grooves 82c being parallel to the axis of the opening 28. Each of the arcuate sections 82, 84 and 86 also has an outwardly extending central tab 85 spaced from the parts 26, 24, and 22, respectively. These tabs 85 extend in a plane which is parallel to the plane of the opening 28 and they facilitate retaining a clamping member in monted position in abutment with the convex surface of the arcuate wall sections within the space between the tabs 85 and the parts 22, 24, and 26. The region of the convex surface of each of the wall sections 82, 84 and 86 adjacent to the tab 85 thereof is not grooved, thus forming an arcuate land 89.

The clamping member 90 has an annular ring 92 formed by a discontinuous curved position which terminates at the discontinuity designated 92a and 921;. A first integral bar portion 94 extends from terminating edge 92b, and a second integral bar portion 96 extends from terminating edge 92a. The inside or concave side of the ring 92 has a plurality of spaced serrated areas arranged in spaced pairs. These serrated areas 98a and 98b are formed by outwardly extending straight ridges 99 disposed parallel to the axis of the opening 28 and adapted to mate with the grooves 820. Also, each of the areas 98a and 98b of the ring has the same number of ridges 99 as the areas 82a and 82b have grooves, and the same spacing between areas and between ridges. The inside of the ring also has a pair of spaced ribs 100 disposed between each pair of areas 98a and 98b. The longitudinal axes of these ribs 100 are disposed normally to the plane of the ring 92. Each pair of ribs 100 are disposed in abutment with the beveled side edges of different and adjacent arcuate section walls, the edges being designated 102 and 104 on each arcuate section wall 82, 84 and 86. The ribs 100 cooperate with the beveled edges by riding up and down the high and low surfaces of the beveled edges 102 and 104 in accordance with the increase or decrease in diameter size of the neck of the tube, thus providing uniform pressure on each section wall and maintaining each of the parts 22, 24 and 26 at an angle of precisely to the adjacent parts, which is necessary for color purity. The beveled surfaces 102 and 104 are flat surfaces disp sed t an acute angle of approximatel 45 to a radial plane of the opening 28 at the surface 102 or 104.

Elongated bar portions 94, 96 of the clamping member are adjustably moved relative to each other by actuating a screw 106. The shank 108 of the screw moves freely in an enlarged bore 110 in bar 96 and threadably engages a tapped bore 112 in bar 94. A protuberance 113 extending from bar 96 toward bar 94 on the side of the screw 108 opposite the ring 92 forms a pivot point upon which bar 94 bears when screw 108 is tightened. As the bars 94, 96 are positioned closer to each other, the end of the bar 94 adjacent to the ring discontinuity 92b is forced toward the bar 96 in the manner of a second order lever, and hence the diameter of the annular ring 92 is decreased to attain a tighter clamping action against arcuate wall sections 82, 84, and 86. This clamps the convergence assembly tightly on the neck of the tube, and the clamping operation is achieved by operating the screw 106 on the elongated bars 94 and 96 at a point remote from the neck of the television tube and away from the congestion which surrounds the necks of virtually all television tubes when mounted in a receiver.

When the clamping member 90 is securely positioned, the ridges of the serrated areas 98 on the inside or concave surfaces of the ring 92 interlock with the corresponding grooves of the serrated areas on the outside or convex sides of the arcuate wall sections 82, 84, and 86. The mating of the serrated areas and the engagement of the ridges 100 with the beveled edges 102 and 104 of the wall sections 82, 84 and 86 prevents rotational changes of the parts 22, 24 and 26 of the convergence assembly relative to each other which is an important consideration for color purity. However, the entire convergence assembly may be rotated relative to the neck of the picture tube by partially loosening the screw 108 and rotating the bars 94 and 96 without changing the angular relation of the parts 22, 24 and 26.

The tabs 85 on arcuate wall section 82, 84 and 86 abut the top edge of the clamping ring 90 to thereby effectively prevent displacement of the clamping member along the longitudinal axis of the neck of the television tube or from the parts 22, 24 and 26 prior to assembly on a picture tube. The released or open position of the clamp 92 for mounting on a picture tube is shown in FIGURE 4. In this view, the parts 22, 24 and 26 are indicated as being partially separated by the non-abutting pos t on of edge 39 and shoulder 37 of the displacement limiting means. It will be understood that in the tightened positlon, the bar 94 engages the protuberance 113 of the bar 96.

The invention may now be practiced in the many various ways which occur to those skilled in this art, and all such modifications in practice will comprise a part of the concept behind the disclosed embodiments. The invention is now defined by the terms of the following claims which are given further meaning by the language of the preceding description.

The invention claimed is:

1. A convergence assembly adapted to be mounted on the neck of a multiple gun cathode ray tube, including a plurality of housing parts equal in number to the number of guns of the cathode ray tube, the inner end of each part terminating in a part cylindncal surface with a common radius of curvature, each of the parts carrylng a convergence coil assembly for use in a dynamic convergence system for one of the guns of the cathode ray tube, each part having an elongated locking lug projecting from one side of the part cylindrical surface thereof with the longitudinal axis of the lug disposed approximately normal to the central axis of the part cylindrical segment of said part, each part having a complementary locking chamber on the other side of the part cylindrical surface thereof, the locking lug of each part being disposed within and engaging the locking chamber of one of the other parts and restricting movement of the lug to translation along the axis of elongation thereof, the

parts thereby being mechanically interconnected to maintain the central axes of the part cylindrical surfaces parallel to each other to form a central opening between the parts, translation of the lugs within the chambers of the parts altering the size of the opening so the assembly can be mounted on cathode ray tube of different diameters, and locking means mechanically associated with each part for securing the parts in fixed positions in abutment with the neck of a cathode ray tube.

2. A convergence assembly for a cathode ray tube having three guns disposed about the axis of the neck of the tube and being equally spaced from each other comprising the combination of claim 1 wherein three housing parts are employed, each of the parts having a coil assembly producing a magnetic field in the central radial plane of the part cylindrical surface, and said radial planes being maintained at angles of approximately to each other.

3. A convergence assembly comprising the combination of claim 1 in which the locking means includes an arcuate wall section on each inner end of each part, said section extending normally to the plane of the central opening at the perimeter of the opening, and having a curved surface continuous with the part cylindrical surface and of the same curvature, an annular clamp engaging the sides of the arcuate sections opposite the opening and means to urge the annular clamp against the arcuate wall sections.

4. A convergence assembly comprising the combination of claim 3 in which the sides of the arcuate wall sections opposite the opening are part cylindrical and are provided with serrations, and the inside of the annular clamp has serrations adapted to mate with the serrations of the arcuate wall section when the clamp engages the wall sections.

5. A convergence assembly comprising the combination of claim 4 wherein the serrations on the wall sections are formed by a plurality of linear equally spaced grooves disposed parallel to the central axis of the part cylindrical surface, and the serrations on the annular clamp are formed by a plurality of linear protruding ridges spaced by the same distance as the grooves and mating with the grooves.

6. A convergence assembly comprising the combination of claim 3 wherein the annular clamp member comprises a ring having a gap therein and two bars extending generally parallel to each other from opposite sides of the gap in the ring, in combination with means to adjustably position the bars relative to each other to thereby decrease and increase the diameter of the ring.

7. A convergence assembly comprising the combination of claim 6 wherein one of the bars has a protuberance adjacent to the end thereof opposite the ring confronting the other bar, and the means for positioning the bars comprises a screw mechanism operable between the bars located between the protrusion and the ring.

8. A convergence assembly comprising the combination of claim 3 wherein each arcuate wall section is provided with a tab extending outwardly from an edge of the arcuate wall section and spaced from the part thereof, and said tab slidably abutting one edge of the ring to hold the ring between the tab and the part, said ring being removable from the arcuate sections by increasing the diameter of the ring.

9. A convergence assembly comprising the combination of claim 3 wherein the annular clamp has a plurality of pairs of parallel protruding linear ribs spaced on the inside of the annular clamp, the longitudinal axis of said ribs being normal to the plane of said central opening, said ribs being of each pair being disposed between two adjacent arcuate wall sections, each of said wall sections having linear edges extending normal to the plane of the opening, the ribs of each pair being disposed between the linear edges of adjacent sections and engaging said linear edges.

References Cited UNITED STATES PATENTS- 12/1958 Lazzery 3352l0 XR 2/1967 Leeb et al. 335212 10/1967 Babcock et al. 335--2l2 XR GEORGE HARRIS, Primary Examiner US. Cl. X.R. 

